The present disclosure relates to an electrophoretic device that includes a plurality of electrophoretic particles in an insulating liquid and to a method of manufacturing the electrophoretic device. The present disclosure also relates to a display that includes the electrophoretic device.
In recent years, a demand for a display with low power consumption and high-grade image quality has been increased as a result of widespread use of mobile devices typified by devices such as mobile phones and personal digital assistants. In particular, a personal digital assistant (an electronic book terminal) for reading application in order to read character information for a long time has attracted attention recently as a result of launch of the distribution service of the electronic books. This leads to a demand for a display that has a display grade suitable for such an application.
As a display for reading application, a display such as a cholesteric liquid crystal display, an electrophoretic display, an electrochromic display, and a twist-ball display has been proposed. In particular, a reflective display is preferable. One reason is that this provides a display grade similar to that of paper since the reflective display performs light display by utilizing reflection (scattering) of outside light as paper does. Another reason is that this lowers electric power consumption since a backlight is not necessary in the reflective display.
A major candidate of the reflective display is the electrophoretic display that creates contrast by utilizing an electrophoresis phenomenon. One reason for this is that the electrophoretic display achieves low electric power consumption and is superior in high-speed response. Hence, various studies have been made on a display method of an electrophoretic display.
Specifically, a method has been proposed in which two types of charged particles that have different optical reflection characteristics are dispersed in an insulating liquid, and the charged particles are transferred in response to an electric field (for example, see Japanese Examined Patent Application Publication No. S50-015115 and Japanese Patent No. 4188091). In this method, a distribution state of the charged particles varies in response to the electric field since the two types of charged particles have polarities opposite to each other.
Further, a method has been proposed in which a porous layer is arranged in an insulating liquid and charged particles are dispersed in the insulating liquid, and the charged particles are transferred through fine pores of the porous layer in response to an electric field (for example, see Japanese Unexamined Patent Application Publication Nos. 2005-107146, 2005-128143, and 2002-244163, and Japanese Examined Patent Application Publication No. S50-015120). In this method, for example, a polymer film that has fine pores formed by laser drilling, fabric woven with a material such as a synthetic fiber, an open-cell porous polymer, or the like may be used as the porous film.